Fruit juices contain about 85 wt %, or more, water, with the remaining composed of volatile organic compounds, organic acids, aroma, flavour, sugars and fibre, as well as many other constituents in trace quantities. The extraction of juice from fruit or vegetable is a common industrial activity. The extracted juice is typically concentrated to form a concentrated juice using one or more of several commercial processes, some more efficient than others.
The process of concentrating the extracted juice to form a concentrated juice also forms a concentrator waste stream. The composition of this concentrator waste stream varies and is contingent on the efficiency of the concentration process, and may have the characteristic smell and/or taste of the fruit or vegetable or sugar cane juice from which it originated. That is, a less than 100% efficient concentration process (where all non-water constituents are desirably retained with the concentrated juice) results in a concentrator waste stream that is predominantly water but which also contains some source fruit or vegetable or sugar cane constituents. Typical carry over constituents include aroma and other volatiles, organic acids, and sugars; the exact composition contingent on the separation process used. In practice, 100% efficiency of the concentration process is not achieved.
Due to the organic contaminants, this concentrator waste stream is susceptible to fouling due to oxidation and microbial contamination. Thus, if later use of the concentrator waste stream is desired it is necessary to add preservatives. For instance, the concentrator waste stream may be used in the wine industry if preserved through acidification and sulphur dioxide addition, but even this only offers a short term storage solution. Most typically, the concentrator waste stream is discarded as waste water.
WO94/19967 relates to the use of the concentrator waste stream as potable water. In this document it is stated that it is desirable to provide a process for providing pure water which can be distributed to the consumer. However, the only such process referred to in the document is a particular process for concentrating extracted juice, namely a four stage evaporation system, and the process for providing pure water is merely the condensation of steam from this evaporation system. Pasteurisation, micro-filtration, and/or carbonation are optional post-processing steps.
WO2009/155675 describes processes to recover water in the context of commercial sugar production and ethanol production and is not directed to processes for recovering water from a process stream having a relatively high concentration of sugar.
US2005/308793 describes processes for treating an oil shale and is not relevant to the field of the present invention.
US2010100090 and US2005/0274675 are directed to process for producing a product from water that is already potable. These processes are therefore unsuitable for treating a water that is not potable, not suitable or is not palatable.
It is desirable to provide a process for recovering potable storable water from a concentrator waste stream formed in a process of concentrating an extracted juice, particularly in instances where the concentrator waste stream is not already potable storable water upon formation.
The discussion of documents, acts, materials, devices, articles and the like in this Background section is included in this specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters formed part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application.